#include <iostream>
using namespace std;

int main()
{
  cout.setf(ios::fixed);
  cout.setf(ios::showpoint);
  cout.precision(13);

  double sumProb = 0;
  for(int i = 0; i < 23; i++)
  {
    for(int j = i + 1; j < 24; j++)
    {
      for(int k = j + 1; k < 25; k++)
      {
        double prob = 1;
        for(double l = 0; l < 25; l++)
        {
          if(l == i || l == j || l == k)
          {
            prob *= ( 1 / (100 - l));
          }
          else
          {
            prob *= ( (99 - l) / (100 - l));
          }
        }
        sumProb += prob;
      }
    }
  }
  cout << sumProb << endl;
  return 0;
}
